``Have they found it?'' will be the query of most readers. The answer is no--not by a long shot--although Boaz (Anthropology/George Washington University) shows that knowledge about early humans has leaped dramatically during the last generation. The Rubicon was 1950, when biological anthropology was born at a conference at Cold Spring Harbor. This new science replaced the old method of studying fossil human specimens--by endlessly categorizing them into ever-finer types--with new disciplines that situated early humans in their social and ecological context. What ancient people ate, when they hunted, even how they made love became issues in the new paleoanthropology, aided by advances in geology, ethology, and taphonomy (the study of how fossils are created and preserved), as well as by new dating methods. Boaz argues strongly for biological anthropology and its tenets, the most controversial of which is that human behavior--gang warfare, for instance--is ``hardwired,'' a result of evolution and natural selection rather than social conditions. Readers will take note, too, of Boaz's chiding of leading paleontologists, including Richard Leakey (for being dictatorial), Stephen Jay Gould (for relying on armchair science), and Donald Johanson (for faulty dating). His own adventures on long, weary, dusty digs in Zaire and Libya are recounted with verve as he addresses key questions--Why did bipedalism develop? What role did climate play in our origins? --and makes his case that humans arose in East Africa 2.5 million years ago. Peppery, informative bones of contention.